She realizes that Edgar's kindness and gentleness is unsuitable for her own nature: "I've no more business to marry Edgar Linton than I have to be in heaven: and if the wicked man in there had not brought Heathcliff so low, I shouldn't have thought of it. It would degrade me to marry Heathcliff now.... "(Bronte, 95) in her understanding, she could never be at peace in heaven, because her passions are not mild or harmonious. She and Heathcliff belong among the wild forces of nature and their love cannot exist in the middle of society. Moreover, Catherine feels that her bond with Heathcliff is so strong as to be able to unite them into a single soul. Their oneness further explains the fact that they are not actually compatible in the social environment. The identities of Catherine and Heathcliff obviously merge, forming a singular dependence or addiction: "So he shall never know I love him: and that, not because he's handsome, Nelly, but because he's more myself than I am. Whatever our souls are made of, his and mine are the same; and Linton's is as different as a moonbeam from lightning, or frost from fire." (Bronte, 95) as Debra Goodlett emphasizes, the nature of their love could be called "an addiction," since it absorbs a part of each of their identities: "The intensity arises out of the bond between Catherine and Heathcliff, a bond which can best be described as an addiction rather than as a "theme" of a traditional Romantic Gothic novel."(Goodlett,...

I know that ghosts have wandered on earth. Stay with me always -- take any form -- drive me mad! Only do not leave me in this abyss, where I cannot find you! I cannot live without my soul!" (Bronte, 203) Catherine and Heathcliff cannot live apart as their symbiosis is so complete, but neither can they live together in the midst of social convention. Their love transcends the conventional bond precisely because of its pure, unalloyed and natural force. As Carole Gerster notes therefore, the two lose their earthly paradise of innocence when they have to assume their gender role and separate: "Their childhood paradise is shattered by their separation and their subsequent fall into conventional gender roles. Despite these transformations, however, both Catherine and Heathcliff long for a return to their original androgynous relationship."(Gerster, 16) Thus, Catherine and Heathcliff have a primitive or primordial love, which however is not merely instinctual or naturalistic, but rather wild and untouched by social convention and the effects of civilization.
Works Cited

Bloom, Harold. Emily Bronte's 'Wuthering Heights'. New York: Chelsea House Publishers, 1987.

Bronte, Emily. Wuthering Heights. New York: Washington Square Press, 1964.

Gerster, Carole. "The Reality of Fantasy: Emily Bront's Wuthering Heights." Exploring Novels. Online ed. Detroit: Gale, 2003.

Goodlett, Debra. "Love and addiction in 'Wuthering Heights.'." The Midwest Quarterly 37.n3 (Spring 1996): 316(12)